Hydraulic tipping mechanism for vehicles



V. P. BOURNE VAN NECK HYDRAULIC TIPPING MECHANISM FOR VEHICLES July 19,149.

2 Sheets-Sheet 1 Filed Dec. 8, 1944 v. P. BOURN E-VAN NECK 2,476,594

mumc TIPPING MECHANISM FOR VEHICLES July 19, 1949,

HYD

2 Sheets-Sheet 2 Filed Dec. 8, 1944 Patented July 19, 1949 2,476,694 I FF l C E HYDRAULIC TIPPIN G MECHANISM FOR VEHICLES Vincent 1.Bourne-Vanneck, London, England Application December 8, 1944, Serial No.567,194 In Great Britain April 14, 1943 Section 1, Public Law 690,August 8, 1946 Patent expires April 14, 1963 3 Claims. 1

This invention relates to hydraulic tipping mechanism for vehicles withmore especial reference to slant-type hoists wherein the body is raisedand lowered about pivots at the rear end of the vehicle chassis by anhydraulic ram assembly trunnioned on a cross member of the vehicle andarranged at an angle between the chassis and the body of the vehicle.

Slant-type hoists of this character are advantageous in that they needlittle vertical space for their accommodation and so permit of arelative- 1y low loading platform, but in use they suffer from thedisadvantage that considerable rearward thrust is imposed on the rearbody pivots by the hydraulic mechanism, particularly during initialmovement of the body for tipping owing to the obtuse angle of the ramunder these conditions, so that not infrequently crystallisation of thebearing brackets and premature failure ensues.

The present invention has for its object to remove this disadvantage andprovide an improved slant-type hydraulic tipping mechanism with whichthe stresses are more uniformly distributed, and the rear brackets andpivots are relieved of strain during the initial movement.

Hydraulic tipping mechanism for vehicles according to the presentinvention essentially includes, in addition to a slant-type ram assemblybetween the vehicle chassis and the body frame, a supplementary ramhaving its axis approximately vertical and abutting the end of the bodyframe remote from the pivot for the initial lifting thereof withoutbeing attached thereto, said supplementary ram being incorporated in thehydraulic system in such manner as directly to lift the front part ofthe body during the initial tipping movement thereby relieving the rearbody pivots of the considerable stress to which they are normallysubject.

The mounting of the slant-type ram assembly is correspondingly relievedof stress owing to the initial lifting of the fore end of the body bythe supplementary ram and, as will be understood, the ram assembly andits mounting may thus be of reduced overall gauge and weight withconsequent lowering of its cost of manufacture.

Alternatively, a main ram of shorter stroke can be used with its bodyanchorage in closer proximity to the body-pivotgiving a higher velocityratio owing to the fact that the supplementary ram affords the requisitemechanical advantage during the initial lifting of the body.

The supplementary ram assembly advantageously comprises a cylinder andram, preferably telescopic, trunnioned with, but having its axisapproximately at right angles to, the main slant-type ram, thetelescopic ram of the supplementary cylinder terminating at its upperend in an abutment adapted to bear under a thrustplate provided for thepurpose on the underside of the body near the front thereof, the twocylinders being coupled in parallel in the hydraulic system in suchmanner that-when set for tip ping-the hydraulic medium under pressurefirst passes intothe supplementary cylinder causing an upward movementof its ram which directly lifts the front end of the body about its rearpivots. Subsequently after the limit of movement of the supplementaryram has been reached, the hydraulic medium is forced into the maincylinder and thence-forward operates the slanttype ram in theconventional manner until the full tipping angle, say 55 has beenattained.

During lowering the procedure is reversed, the movement of the bodybeing controlled by the slant-type ram until it reaches the position, atsay 15 from the horizontal, at which the aforementioned thrust platebears on the abutment of the supplementary ram whereafter furtherdownward movement of the body to the normal horizontal position isregulated by the supplementary ram assembly.

The invention will be further described with reference to theaccompanying drawings which illustrate by way of example two embodimentsthereof and in which:

Figs. 1 and 2 show a preferred embodiment where the supplementary ram iscombined with the main slant-type ram assembly as a single rocking unit.

Fig. 1 being a side elevation of the rear portion of a tipping vehicleequipped with the improved mechanism, and

Fig. 2 is a detail view to a larger scale while Fig. 3 is a diagrammaticrepresentation of an alternative arrangement where the supplementary ramcylinder is mounted on the vehicle chassis separately from the mainslant-type ram.

Referring now to the drawings, but first more particularly to Figs. 1and 2, the vehicle chassis is designated l and the vehicle body 2, 3being the body frame and 4 one of the body pivots carried by a bracket 5mounted on the rear end of the main longitudinal member of the chassisI. 6 is the body rear bracket depending from the body frame 3 and ridingabout the body pivot 4 during the tipping movement, while 1 represents aslant-type ram cylinder fulcrumed at 8 on a main cross member 9 of thevehicle chassis on the one hand, and having a ram head l0 engaging athrust block I l on the body frame 3 in front of the body pivot i on theother.

As will be understood, when fluid under pressure is'admitted to thelower end of the ram cylinder 1 from the hydraulic system (not shown)which may be of any usual form through a connection such as l2, the ramis forced outwardly and the ram head l0 causes the body to be tippedabout the rear pivot 4 as represented by the dot and dashzshowing inFig. l, the maximum tipping angle usually being of the order of 55".

To obviate the disadvantage present with the slant-type hoists whereconsiderable rearward thrust is imposed on the body pivots l,particularly during initial movement ofthe body 2 for tipping, owing tothe obtuse angle of the ram under these conditions, the presentinvention provides a supplementary ram cylinder 55 which has its axisapproximately vertical and is incorporated in the hydraulic system insuch manner as directly to lift the front part of the body during theinitial tipping movement.

In this embodiment the supplementary ram cylinder i is combined as aunit with the main ram cylinder i, a common casting it mounting both themain'ram cylinder 1 and the supplementary ram cylinder at an angle ofcirca 70 to each other so that they rock in unison about the fulcrum 8which takes the form of journals projecting at each side of the castingIt.

With the body frame 3 in the position which it occupies when .the body 2is lowered to its normal horizontal position as shown by the full lines,

1e axis of the supplementary ram i5 is vertical and on the tipping valvebeing opened to admit fluid under pressure to the casting It through theconnection l2, the supplementary ram-which is shown as of two parttelescopic construction and is designated ll and l8-bears under. athrust plate 13 provided for the purpose on the underside'of the bodyframe 3 near the front of the body and directly lifts the front end ofthe body about its rear pivot a.

.At the limit of movement of the supplementary ram I5, I! and I8,corresponding in the embodiment illustrated to an inclination of 15, themain ram continues the tipping movement of the vehicle body and at thisphase the main ram assembly is in a position for the ram head it toexert considerable turning moment about the body rear pivot 4- to swingthe body to its maximum tipping position.

During lowering theprocedureis reversed, the movement of the body 2being controlled by the slant-type ram untilit reaches the position at15 from the horizontal when the thrust plate l3 near the front end ofthe body bears on the head of the supplementary ram ll, l8 whereafterfurther downward movement of the body to the normalposition is,regulated by, the supplementaryram.

In this-preferred embodiment where the main and supplementary ramassemblies rock as a unit about the fulcrum. 8, upward displacement ofthe axis of the main ram causes the assembly to swing in acounter-clockwise direction about the fulcrum 8 with the consequencethat the axis of the supplementary ram is inclined forwardly during thetipping and it is necessary to afford sufficient clear space toaccommodate this forward oscillatory movement.

Alternatively however as shown in Fig. 3, the supplementary ram cylinder15 may be a fixture carried by the vehicle .cross member 9 in which caseits axis remains vertical throughout its operative stroke.

The cylinders .oithe main slant-type ram and the auxiliary or"supplementary ram may be connected in parallel 'in the hydraulic systemso that on the control valve of the system being set to effect tipping,the medium under pressure may flow into both cylinders but owing to theincreased resistance to movement of the main ranithe fluldpa'sses firstintothe supplementary cylinder l5 and elevates the supplementary ram ll,it directly to raise the body during the initial tipping movement, whileat the limit of the stroke of the supplementary ram the fluid passesinto the main cylinder 1 to complete the tipping movement. If desiredhowever, the fluid may be fed first into the cylinder [5 and at or aboutthe upper limit of travel of the supplementary ram ll, 83, cause it touncover a port communicating with the main cylinder 7. Further, the pumpmay be combined with the ram assembly as a unit rocking about thefulcrum 8 thereby reducing or even eliminating separate piping for thehydraulic medium.

Where desired also, means may be associated with the supplementary ramabutment on the thrust plate :19 to lock the body in its horizontalposition for loading and transport and such means may be releasedautomatically on the control lever of the gear being set to the tippingposition thus to actuate the supplementary cylinder.

By the present invention an improved economical and eflicient'hydraulictipping gear for vehicles is obtained.

What Iclaim is:

i. Tipping mechanism fora vehicle having a body frame pivotally mountedin the vehicle chassis, a slant-typegram assembly between the vehiclechassis and the pivoted body frame, and

a hydraulic system for operatingsaid ram assembly to raise and lower thebody, includin a supplementary ram disposed further from the body pivotthan the slant-type ram and arranged with its axis approximatelyvertical and with its upper end abutting the body frame for the initiallifting thereof Without being attached thereto, said supplementary rambeing incorporated in the hydraulic system in such manner as directly tolift thebody to effect the initial tipping moveand the continued liftingmovement of the body being effected byv the slant-type ram withoutfurther extension or following movement of the supplem ntary ram- 2.Tipping mechanism for vehicles according to claim 1 wherein-thesupplementary ram as sembly comprises a telescopic ram terminating atits upper end in an abutment adapted to bear under a thrust-plateprovided for :the purpose on the underside of the body near the frontthereof,

the two ram cylinders being coupled in the hydraulic systemvin.such.manner. that-when set for tipping-the hydraulic. medium underpressure first passes into the supplementary cylinder causing anupward-movement of, its ram which directlyliftsthe :front end ofthe bodyabout its rear pivots.

3. Tipping mechanism for vehicles according to claim '1 whereinthe-supplementary ram assembly is trunnioned as aunit with the main ramassembly and rocks therewith during tipping.

VINCENT P BOURNE-VANNECK.

REFERENCES CITED The following references. are of record in the file ofthis patent;

UNITED STATES PATENTS Number- Name Date 1,482,510 Edwards e Feb. 5, 19242,220,815 Feilcke Nov. 5, 1940 2,326,594. Wood Aug. 10, 1943

